Impregnated indexing roller for grinding wheel dressers



Ami? H, 3%? R. E. PRICE ETAL IMPREGNATED INDEXING ROLLER FOR GRINDING WHEEL DRESSERS 5 Sheets-Sheet 1 Filed April 27, 1964 Rh Eu Am-iii H, 1 .9%? R. E. PRICE ETAL 3,333,2g5

IMPREGNATED INDEXING ROLLER FOR GRINDING WHEEL DRESSERS Filed April 27, 1964 '5 Sheets-Sheet 2 INVENTORS RALPH E. P/P/CE BY WILLIAM R FLO/1i? JR.

ATTORNEY W y Fififi? R. E. PRacE ETAL 3,3i3,Z%3%

IMPREGNATED INDEXING ROLLER FOR GRINDING WHEEL DRESSERS Filed April 27; 1964 5 Sheets-Sheet 5 INVENTORS RALPH .2. PRICE B WILL/AP!) P. F am? JE.

ATTORNEY Awiii 9 119%"? R. E. PRICE ETAL 3,3132%5 IMFREGNATED INDEXING ROLLER FOR GRINDING WHEEL DRESSERS Filed April 27, 1964 5 Sheets-Sheet 4 I..: LJ

INVENTORS RALPH z. w/cs By WILLIAM P. F1. 0m? m.

TTORNEY Apwii M 3%?67 R. E. PRICE ETAL 3,313,235

IMPREGNATED INDEXING ROLLER FOR GRINDING WHEEL DRESSERS Filed April 27, 1964 5 Sheets-Sheet 5 !NVENTOR5 RALPH E. PIP/5E BY WILLIAM F LOH)? JR.

United States Patent Fiied Apr. 27, 1954, Ser. No. 362,677 6 Claims. ((31. 125-11) The invention relates to dressing tools for grinding wheels, particularly dressing tools of the type comprising a rotatable cylindrical disc or roller having uniformly distributed cutting particles.

The dressing tool in the form of a roller or wheel may be arranged for continuous rotation by a motor as in US. Patent 3,121,423, granted Feb. 18, 1964. In this invention, the dressing roller is held in fixed angular position during a dressing operation and is rotated incrementally between dressing operations by an indexing device such as a one-way clutch or other suitable mechanism. Where circumstances require rotation of the dressing roller by a motor, the one-Way clutch does not interfere with such rotation. In many cases, the motor may be omitted.

In the prior art, indexing devices actuated both manually and mechanically have been used for indexing single point diamonds. The only reason for indexing a single point diamond is to present diiferent portions of the same large cutting particle to the grinding wheel to change from a worn fiat surface on the particle to a sharp edge on said particle. The diamond turner is not intended to solve the problem of heat and wear which occurs in a single point diamond during a single pass across the grinding wheel. Such wear causes a taper to be dressed on the grinding wheel. In order to avoid dressing a taper on a grinding wheel, many single point dressing devices have been replaced by continuously rotated diamond impregnated tools.

The continuously rotating tool represents an entirely different approach to the problem of dressing a grinding wheel. It presents a plurality of continuously changing sharp cutting elements to the grinding wheel, distributing the cutting action of the dressing tool over a large number of small easily cooled cutting particles, and producing a result not possible with single point diamonds. With this device, the problems of taper due to diamond wear in a dressing operation is eliminated.

In the present invention, the dressing roller is held in a fixed angular position during a dressing operation and is rotated by increments so that a different portion of the dressing roller is presented to the grinding wheel for each dressing operation. Each portion of the roller presents a different combination of cutting particles to the grinding wheel. With this arrangement, the advantage of the continuously rotating tool, presenting a plurality of cutting particles to the grinding wheel, is retained and dressing of a straight face on the wheel is accomplished without the need for continuous rotation of the dressing roller.

Indexing the dressing roller from one fixed angular position to another presents additional advantages. The quality of a dressing operation as determined by work finish is a decided improvement over that obtained from previous dressing devices and methods.

It is an object of the present invention to provide means to improve the quality of the operative surface of a grinding wheel.

Another object is to eliminate taper in the dressing of grinding wheels.

Another object is to provide a dressing device in which dressing will be performed over a plurality of cutting particles.

Another object is to provide a rotatable dressing device which can be indexed from one angularly fixed position to another to present different sets of cutting particles to a grinding wheel.

Another object is to present the dressing roller to the grinding wheel in such a manner that a portion of the dressing roller will retain its original diameter.

Another object is to provide means whereby a dressing roller can be rotated either continuously or incrementally.

The means for traversing the dressing tool across the grinding wheel is shown more in detail in US. Patent 3,122,133, granted Feb. 25, 1964, as well as in US. Patent 3,121,423.

FIG. 1 is a partial plan view in section.

FIG. 2 is a partial end view in section.

FIG. 3 is a diagrammatic sketch of a dresser mechanisrn.

FIG. 4 is a partial end elevation showing the relation between the dressing roller and the grinding wheel.

FIG. 5 is a pneumatic and electric circuit.

FIG. 6 shows the change in point of contact between the dressing roller and the grinding wheel as the dressing roller passes around the corners of the grinding wheel.

FIG. 7 shows the dressing roller with a portion cut away to show the nature of the contact between a new dressing roller and the grinding wheel.

FIG. 8 shows the inclined relation between the dressing roller and the face of the grinding wheel.

FIG. 9 is a plan view in section on line 9-9 of FIG. 2, showing the toothed collar and locking plunger for preventing rotation of the dressing roller during a dressing operation.

In the drawing, FIG. 3, base member 10 is mounted on the grinding wheel support (not shown). Carriage 11 is mounted for movement on base member 10 parallel to the axis of grinding wheel 15. Hydraulic motor 14 provides said movement.

Dresser slide 12 is mounted on carriage 11 for movement transversely of carriage 11 toward and from grinding wheel 15. Slide 12 may be adjusted toward and from grinding Wheel 15 by means of hand wheel 49 and a feed screw (not shown).

Dressing roller 20 is rotatably mounted on shaft 21 in housing 22 and has abrasive cutting particles uniformly distributed in a matrix on its peripheral surface. Dressing roller 29 is arranged to be held in fixed angular position during a dressing operation as will be described in detail later.

Housing 22 is attached by means of adaptor 23 to dresser bar 24 in slide 12. The axis of shaft 21 is inclined slightly to the axis of bar 24 so that the operative face of roller 29 is correspondingly inclined relative to the face of grinding wheel 15. With this arrangement, initial contact between roller 29 and grinding wheel 15 is at the lower edge of roller 2! The inclination of roller 29 is such that at said initial contact, a plurality of cutting particles 86 adjacent the lower edge of roller 29 is presented to grinding wheel 15.

Roller 29 is guided around the corners and across the face of grinding wheel 15 by pattern 30 and roller follower 31 which is the same diameter as roller 20. As roller 29 wears, the entire width of its face is gradually presented to grinding wheel 15 so that there is always a portion of roller 20 which retains the original diameter. This is the same diameter as follower 31. Because this portion of roller 26 is the same diameter as follower 31, the radius dressed on the wheel corners is not afiected by the change in diameter of part of roller 20 due to wear. When roller 2i) becomes worn to the point that its maximum diameter is less than that of follower 31, it is replaced by a new diamond roller.

Pattern 30 and follower 31 are held in operative relation by hydraulic motor 32 which also co-acts with motor 14 to provide the inward component of the traverse movement as roller 20 moves around the wheel corners. Motor 32 may also be used to continue the inward movement of the dresser beyond the completion of the corners, in order to dress the sides of grinding wheel which grind the side walls of a crankpin. The extent of this movement may be determined as shown in US. Patent 3,121,423, by a limit switch 2LS and suitable control means shown more in detail in said patent.

Shaft 21 is rotatably supported in bearings 50 in housing 22. A second housing 25 mounted on housing 22 encloses the index mechanism. At the upper end of housing 25 is supported a driving motor 55 which is connected to shaft 21 through a suitable clutch 58, a disconnectable coupling 56 and shaft 57 which is, in effect, a part of shaft 21.

One means for indexing the dressing roller consists of a one-way clutch 60 on shaft 57 having an index arm 61 attached to rotor 62. Rotor 62 is arranged to drive through balls 63 to shafts 57 and 21 and roller 26. Arm 61 is attached to a piston 65 having head portions 66 and 67. The means for holding dressing roller 20 in fixed angular position consists of a toothed collar 68 on shaft 21 which co-acts with a locking plunger 69 having a double tooth 70 to more precisely engage, center and lock collar 68 and roller 20 in indexed position. During indexing, plunger 69 engages the teeth 71 of collar 68 under the pressure of spring 72 which does not interfere with indexing. During dressing, collar 68 and dress ing roller 20 are locked against rotation by fluid under pressure acting on plunger 69. If the index movement is slightly more or less than the nominal increment, the plunger teeth engaging the teeth on collar 68 Will shift said collar 68 to the proper position.

When desired, roller 20 may be rotated continuously by motor 55 as disclosed in US. Patent 3,121,423. Oneway clutch 60 will not interfere with such continuous rotation. Locking plunger 69 may be retracted for continuous rotation by any suitable device.

Operation The dressing operation is initiated by pressing push button switch P1313 to complete a circuit through normally closed relay contact 92CR2 and normally closed traverse reverse limit switch LS to energize relay 93CR.

Relay contact 93CR2 closes to hold relay 93CR and also to complete a circuit through normally closed relay contact 92CR3 and normally closed relay contact 102CR1 to energize diamond index relay 94CR.

Relay contact 94CR1 in parallel with normally closed relay contact 92CR3 closes to hold relay 94CR.

Relay contacts 94CR2 and 94CR3 complete a circuit to energize index solenoid 25, shifting valve 75 to the right and directing fluid under pressure to the right hand portion 67 of piston 65, shifting said piston to the left and moving index arm 61, rotor 62 and dresser shaft '57 in a counter-clockwise direction.

Operation of the index mechanism closes index limit switch 26LS, completing a circuit to energize relay 92CR.

Relay contact 92CR1 closes to complete a circuit fr9 m relay contact 93CR1 to hold relay 92CR.

Normally closed relay contact 92CR2 opens in the circuit to relay 93CR, but the circuit is held through holding contact 93CR2.

Normally closed relay contact 92CR3 is opened, but relay 94CR is held through relay contact 94CR1 which is in parallel with normally closed relay contact 92CR3.

Relay contact 92CR4 closes in a circuit with previously closed relay Contact 93CR3, to energize traverse right relay 102CR.

Normally closed relay contact 102CR1 opens to deenergize diamond index relay 94CR.

Relay contact 94CR2 opens to deenergize index sole noid 25.

Valve is returned to the left by spring 76 to reset piston 65 and apply pressure through line 64 to locking plunger 69 to lock collar 68 and roller 20 against rotation during a dressing operation.

Relay contact 102CR3 completes a circuit to energize traverse right solenoid 26, shifting reversing valve to the right and directing fluid under pressure to the left end of hydraulic motor 14 to shift carriage 11 to the right.

At the end of the carriage movement to the right, traverse reverse limit switch 25LS is opened to deenergize relay QSCR.

Index limit switch 26LS is opened, but relay 92CR remains energized by a holding circuit through the dresser traverse start limit switch 24LS and relay contact 92CR1.

Relay contact 93CR3 opens to deenergize traverse right relay 192CR.

Normally closed relay contact 93CR4 closes to complete a circuit from relay contact 92CR4 to energize traverse left relay 103CR.

Relay contact 103111 closes to energize traverse left solenoid 27, shifting reversing valve 85 to the left and directing fluid to the right hand end of hydraulic motor 14 to shift carriage 11 to the left.

At the end of the traverse movement to the left, limit switch 24LS is opened to deenergize relay 92CR.

Relay contact 92CR4 opens in the circuit to traverse left relay 103CR.

Relay contact 103CR1 opens to deenergize traverse left solenoid 27.

Reversing valve 85 returns to central position.

As the cutting particles 30 of roller 20 pass across the face of grinding wheel 15, point A of the roller engages grinding wheel 15 andperforms the dressing operation. As roller 29 moves around the left hand corner of grinding wheel 15, the point of contact of roller 20 changes from point A at the beginning of the corner dressing, through a distance of to point B at the end of the corner dressing operation.

During the next pass, point A again dresses the face of the grinding wheel 15. When roller 20 starts around the right hand corner, the point of contact shifts 90 from point A to point C.

Since dressing roller 20 is indexed, in this case 6, before each dressing operation, the portion of the roller performing the dressing operation either on the face or on the corners, is continuously changing. Distribution of the corner dressing operation over 90 of the dressing roller 20 along with the fact that the tool is inclined insures that a portion of the roller will always have a radius the same as follower 31 and assures accuracy and superior finish in the fillets or radii of the workpiece.

We claim:

1. Means for dressing a grinding wheel comprising (a) a dressing roller mounted for rotation in a plane normal to the plane of said grinding Wheel with its peripheral face inclined so that initial engagement of said roller with the peripheral face of said grinding wheel is on one edge of said roller,

(b) said roller having a diamond impregnated continuous peripheral surface,

(0) means for moving said roller toward and from said grinding wheel along a path passing through the axis of said grinding wheel,

(d) a longitudinally movable carriage for traversing s-aid roller across said grinding wheel,

(e) an incremental device operable at one end of said longitudinal movement for rotating said roller to present difierent portions of said roller to said grinding wheel,

(f) and means to hold said roller in a fixed angular position as it passes across said grinding wheel.

2. Means for dressing a grinding wheel having rounded corners comprising a) a dressing roller mounted for rotation in a plane normal to the plane of said grinding wheel and having a plurality of rows of uniformly distributed cutting particles on its peripheral surface,

(b) a longitudinally movable carriage for traversing said roller across said grinding wheel for a dressing operation,

(c) means for feeding said roller toward said grinding wheel,

(d) a pattern and roller follower for guiding said dressing roller around said corners,

(e) means for maintaining a portion of said roller the same diameter as said roller follower comprising (f) means for supporting said roller in an inclined position such that initial engagement of said roller with the peripheral face of said grinding wheel is on a portion only of the operative face of said roller,

(g) means to locate and hold said roller in a fixed angular position including an index device for turning said roller to another fixed angular position to present different combinations of cutting particles to said grinding wheel,

(11) and control means operable in response to said means for turning said roller, for initiating the longitudinal movement of said carriage.

3. Means for dressing a grinding wheel comprising (a) a dressing roller mounted for rotation in a plane normal to the plane of said grinding wheel With its peripheral face inclined so that initial engagement of said roller with the peripheral face of said grinding Wheel is on one edge of said roller,

(b) said roller having a plurality of rows of uniformly distributed cutting particles on its peripheral surface,

(c) means for moving said roller toward and from said grinding wheel along a path passing through the axis of said grinding wheel,

(d) a longitudinally movable carriage for traversing said roller across said grinding wheel,

(6) an incremental device operable between dressing operation for rotating said roller to successive positions to present diiferent combinations of cutting particles to said grinding wheel,

(f) and means actuated by operation of said incremental device to start said longitudinal movement of said carriage.

4. Means for dressing a grinding wheel comprising (a) a dressing roller mounted for rotation in a plane normal to the plane of said grinding wheel and having a plurality of rows of cutting particles on its peripheral face with its peripheral face inclined so that initial engagement of the roller with the peripheral face of said grinding wheel is on one edge of said roller,

corners comprising (a) a dressing roller mounted for rotation in a plane normal to the plane of said grinding Wheel with its peripheral face inclined so that initial engagement of said roller with the peripheral face of said grinding wheel is on one edge of said roller,

(b) a pattern and roller follower for guiding said roller around said corners,

(c) means for feeding said roller toward said grinding wheel,

(d) a longitudinally movable carriage for traversing said roller across said grinding wheel,

(e) an incremental device for rotating said roller,

(f) and control means operable by said incremental device for initiating the longitudinal movement of said carriage.

6. Means for dressing a grinding wheel having rounded corners comprising (a) a dressing roller mounted for rotation in a plane normal to the plane of said grinding wheel and having a plurality of rows of cutting particles on its peripheral face, with its peripheral face inclined so that initial engagement of said roller with the peripheral face of said grinding wheel is on one edge of said roller,

(b) a pattern and roller follower for guiding said roller around said corners,

(c) means for feeding said roller toward said grinding wheel,

(d) a longitudinally movable carriage for traversing said roller across said grinding wheel,

(e) an incremental device operable between dressing operations for rotating said roller,

(f) and fluid pressure actuated means to hold said roller in fixed angular position during the dressing operation.

References Cited by the Examiner UNITED STATES PATENTS 2,380,451 7/1945 Koebel -39 2,507,756 5/ 1950 Boylan 74812 2,752,909 7/1956 Curran 125-11 2,933,078 4/1960 Bruce 12511 3,121,423 2/ 1964 Price et a1 125-11.2

HAROLD D. WHITEHEAD, Primary Examiner. 

1. MEANS FOR DRESSING A GRINDING WHEEL COMPRISING (A) A DRESSING ROLLER MOUNTED FOR ROTATION IN A PLANE NORMAL TO THE PLANE OF SAID GRINDING WHEEL WITH ITS PERIPHERAL FACE INCLINED SO THAT INITIAL ENGAGEMENT OF SAID ROLLER WITH THE PERIPHERAL FACE OF SAID GRINDING WHEEL IS ON ONE EDGE OF SAID ROLLER, (B) SAID ROLLER HAVING A DIAMOND IMPREGNATED CONTINUOUS PERIPHERAL SURFACE, (C) MEANS FOR MOVING SAID ROLLER TOWARD AND FROM SAID GRINDING WHEEL ALONG A PATH PASSING THROUGH THE AXIS OF SAID GRINDING WHEEL, (D) A LONGITUDINALLY MOVABLE CARRIAGE FOR TRAVERSING SAID ROLLER ACROSS SAID GRINDING WHEEL, (E) AN INCREMENTAL DEVICE OPERABLE AT ONE END OF SAID LONGITUDINAL MOVEMENT FOR ROTATING SAID ROLLER TO PRESENT DIFFERENT PORTIONS OF SAID ROLLER TO SAID GRINDING WHEEL, (F) AND MEANS TO HOLD SAID ROLLER IN A FIXED ANGULAR POSITION AS IT PASSES ACROSS SAID GRINDING WHEEL. 